NEW YORK, Nov 30 (Reuters) - The first sites in the United States that allow narcotics users to inject drugs under the supervision of trained staff opened in New York City on Tuesday, a move aimed at stemming a surge in overdose deaths. The city"s health department said two sites, both located in Upper Manhattan, may begin operations as of Tuesday. They are run by two existing Syringe Service Providers, organizations that offer a range of services including access and disposal of injection equipment."Overdose Prevention Centers are a safe and effective way to address the opioid crisis," Mayor Bill de Blasio said in the statement. "I"m proud to show cities in this country that after decades of failure, a smarter approach is possible." Citing research, proponents say the sites provide clean, safe places that save lives and can help curb addiction.This is a watershed milestone in the fight to end overdose deaths in New York," Melissa Moore, director of civil systems reform at Drug Policy Alliance (DPA), said in a statement. "If we want to save lives, reduce criminalization, and curb racial disparities, we need comprehensive, innovative, and forward-thinking approaches like Overdose Prevention Centers." Opponents of the sites say they threaten communities in which they are located by facilitating drug use. De Blasio, who leaves office in January after two terms as mayor, has long supported the opening of such sites, following an innovation that Canada and other countries implemented years ago. Incoming mayor Eric Adams voiced support for the concept during his campaign. In addition to allowing users to inject narcotics under supervision, the sites are to provide users with syringes and other supplies, as well as medications to reverse overdoses and treatment options. Last year, overdose deaths in New York City jumped to more than 2,000, the highest number since tracking began in 2000. Nearly 600 people died in the first quarter of 2021, according to preliminary city data, the most in a single quarter. Across the country, the opioid epidemic - which worsened since the coronavirus pandemic hit the United States in early 2020 - has ravaged the lives of millions. More Americans than ever - more than 100,000 - died from overdoses over a recent 12-month period, federal data released earlier this month showed. read more The supply of illicit drugs on the streets has become deadlier, mostly due to widespread availability of fentanyl, which is increasingly mixed with other drugs. Drug consumption services currently operate in 10 countries around the world, according to DPA. Other U.S. cities including San Francisco have plans to open safe injection sites, but none have opened yet. Legal barriers at the federal and state level have hindered efforts to establish supervised consumption services. Earlier this year, a coalition of mayors sent a letter to U.S. Attorney General Merrick Garland seeking clarity on the position of the Department of Justice on a section of the U.S. Controlled Substances Act that says it is illegal to maintain any place for the use of controlled substances.